Electrolytic apparatus



(No Model.)

I. L. ROBERTS.

ELECTROLYTIC APPARATUS.

No. 442,332. Patented Dec. 9, 1890.

I IVENTUHG 'ATTDRNEY$.

WITNESSES:

UITEI) STATas PATENT OFFICE.

ISAIAH L. ROBERTS, OF BROOKLYN, ASSIGNOR OF ONE-HALF TO THOMAS II.MCGRAV, OF POUGI-IKEEPSIE, NEV YORK.

ELECTROLYTIC APPARATUS.

SPECIFICATION forming part of Letters Patent No. 442,332, dated December9, 1890.

Application filed July 13, 1888.

.T all whom it Ina/y con-corn.-

Be it known that I, ISAIAH L. ROBERTS, a citizen of the l'nited States,residing at Brooklyn, in the county of Kings and State of New York, haveinvented certain new and useful Improvements in Electrolytic Apparatus,of which the following is a specification.

IIeretofore attempts have been made to decompose metallic salts or topurify certain solutions by electrolysis; but they have not beensuccessful, for the reason that the apparat us employed has not been ofthe proper character to secure the results sought.

In the attempts heretofore made an electrolytic vat or tank has beenemployed with the anode and cathode in some instances in the samechamber, in others with the anode and cathode separated byan ordinaryporous diaphragm. The reason for the failure of these devices as a meansfor decomposing metallic salts for the production therefrom of alkaliesor alkaline hydrates is their inefficiency in preventing therecombination of the products of decomposition.

My invention differs from these in this respect. I employ a diaphragm orpartition between the two electrodes or electrode-compartments, which,while it is impervious to the solutions and prevents their didusion orintermingling, will interpose practically no obstruction to the desiredelectrolytic action. Diaphragms of this character I designateelectrolytic diaphragms, for the reason that they appear to be capableof acting themselves as electrolytes, and I have used them in galvanicbatteries; but I have made the discovery that they may be employed in.the electrolysis of metallic salts with the results above noted. In thisway I am enabled to obtain better results than are possible with anyother means or process known to me. For instance, by using adecomposable anode, or one that will chemically combine with the acidradical set free by electrolytic action, I may readily and economicallyobtain at a single operation, by the decomposition of a me tallicv salt,an alkali and another metallic salt, both chemically pure, provided thematerials used are pure.

As an example, to produce caustic soda and chloride of iron I use asuitable receptacle Serial No. 279,852. on model.)

divided by a non-porous partition or diaphragm, as above described. Onone side of the partition or diaphragm I place a solution of commonsalt, (chloride of sodium,) with a cathode of any conducting material,such as iron or carbon, that will not be readily attacked by theresultant products of the electro-decomposition. On the other side Iplace an anode of iron in water containing suflicient 6o chloride ofiron (a small quantity will answer) to make it a good conductor. It thena current be passed through the cell from the side of the anode orcompartment inwhich it is intended to produce chloride of iron to thecathode or compartment in which it is intended to pro duce the causticsoda, the following action takes place: The dissociation of the elementsby the electric action has a tendency to deposit metallic sodium uponthe cathode, while the chlorine radical is transferred to the anode andthere-unites with the iron, forming chloride of iron. As it isimpossible to deposit mctallic sodium in the presence of water, thesodium splits or decomposes an atom ot water,and thus produces sodiumhydroxide, (N Ol'L) which will be chemically pure if the salt used wasoriginally pure and the diaphragm of such composition and character asto prevent the diffusion or intermingling of So the liquids on itsopposite sides. So in like manner the sulphate, nitrate, bromide, oxide,

or other salt of any metal may be produced at the same time with all thealkaline hydrates by using the appropriate salts on one side and theproper anode on the other side of the partition or diaphragm.

If it is not desired to produce alkalies, then metals may be deposited.For instance, using sulphate of iron with the cathode and an an- 9 odeof copper, metallic iron will be deposited upon the cathode, while thetransferred acid radical combines with the copper of the anode and formssulphate of copper on the side of the anode. The said radicals,liberated by electrolytic action, cannot be kept separate from theirbases without some form of par tition or diaphragm, their naturaltendency being to reunite and precipitate hydrates when alkalies areobtained, or to deposit metal I on the cathode where metallic salt-scapable of deposit are produced, and while the employment of anypartition contributes more or less to maintaining their separation,according to its degree of porosity, yet I have made the distinctdiscovery that this separation may be maintained complete by making anelectrolytic diaphragm of a non-porous character. Such diaphragms orpartitions I have made partially or wholly of jelly-like or gelatinoussubstances of various kinds, that which I prefer being made in thefollowing manner:

I take a cup, plate, or sheet of very porous or fibrous character, suchas baked earthenware or thick felt, and I saturate it by soaking it forseveral hours-the longer the bet- I terin an aqueous solution of alum. Ithen immerse it in a solution of an alkali, such as caustic soda, untilby the action of the same upon the alum the pores of the porous cup orplate are filled with a gelatinous mass; or I may soak the cup in anaqueous solution of silicate of soda or potash, which should be justthin enough to enable it to penetrate the pores of the cup or plate.Then when the cup is'thoroughly saturated I dipit, say, for

an hour inmuriatic acid or the salts of a metal which has chloride ofiron. These substances cause the silicate to deposit silica in the formof a gelatinous mass in the poresof' the cup or plate.

The diaphragms or partitionsm-ay be made in many other ways and ofvarious other materials, some of which are described in pat-- ents granted to Henry L. Brevoort and myself jointly for improvements in galvanicbatteries, in which the same or similar diaphragms or partitions aremade use of.

My present invention, however, is not directly concerned with thesedetails, being in this respect based upon the discovery that there maybe interposed between the electrodes a diaphragm or partition which willprevent the dilfusion or intermingling of the fluids on its oppositesides, provided it forms in itself an electrolyte orv connecting-link,through which the electrolytic action can take place, and that thus themost useful results are obtained. Such a diaphragm forms a non-poroussubstantially solid homogeneous wall Whose particles, while sufficientlysolid and compact to maintain their own positions and so prevent forpractical purposes any transmission or diffusion of fluids between orthrough them, are yet themselves able to act as electrolytes and suffersuch decompositions and recombinations to take place as are essential tothe electrolytic action by which the result stated is accomplished.

In the accompanying drawing I have shown a conventional form ofelectrolytic cell, by means of which my process may be carried out.

A is the tank or receptacle; B, the non-porous electrolytic diaphragm orpartition, shown in this instance as a porous cup or jar.

G is the cathode and D the anode in the porous cup.

This process is practically useful and valuable as a means of producingcheaply and in apu re state caustic soda, and incidentally a metallicsaltfor example, chloride of iron; but my invention is not limited tothe use or treatment of the materials specified herein, nor to anyothers in particular which in their nature are similar thereto.Furthermore, I regard as immaterial to the invention the specific formor character of the tank and devices by means of which the process iscarried out. I may use any form of diaphragm which, While preventing thedifiusion or intermingling of the fluids on its opposite side, Will notprevent nor injuriousl y retard the electrolytic action.

\Vhat I claim is 1. An electrolytic apparatus for the decomposition ofmetallic salts, consisting in the combination, with a tank or vat, of ananode and cathode and an intermediate non-porous electrolytic diaphragmor partition, as set forth.

2. In an electrolytic apparatus for decomposing metallic salts, thecombination,with the electrodes, of a non-porous diaphragm or partitioninterposed between the electrodes and composed in whole or in part of abody capable of acting as an electrolyte, as set forth.

In an electrolytic apparatus for decomposing metallic salts, thecombination, with a cathode and an anode decomposable by the transferredacidradical, of a non-porous diaphragm or partition between theelectrodes and composed in whole or part of a body capable of acting asan electrolyte.

- ISAIAH L. ROBERTS.

\Vitnesses:

RoBT. l-l. DUNCAN, PARKER N. PAGE,

FRANK B. MURPHY.

